![\"A](\"http:\/\/schools.wrdsb.ca\/athome\/files\/2020\/06\/Calculator.png\")
<\/p>\n<\/p>\n
Annie and Ben are playing. Annie puts her secret number into the calculator without showing Ben.
\nAnnie then asks Ben, “What single digit number do you want to add?”
\nBen tells Annie the number he wants to add.
\n“I want to add four.”<\/p>\n
Annie presses the ‘add’ button and then the four button. The calculator now shows ‘4’. Annie gives the calculator to Ben.
\nBen presses the ‘equals’ button and the calculator gives the answer ’10’.<\/p>\n
What was Annie’s secret number?
\nHow do you know?<\/p>\n
You could play this with a friend. If you figure out the other player’s secret number correctly, it is your turn to put in a secret number of your own.
\nYou could score a point for every one you get right.<\/p>\n
You could start with a 2 digit secret number and ask \u201cWhat single digit number do you want to subtract?\u201d Then press the minus button and the number. Give the calculator to the other player and have them press the equals button and ask them to tell you what your secret number is.<\/p>\n
Adapted from nrich.maths.org<\/a><\/p>\n100 Square Jigsaw Puzzles<\/h2>\n
![\"Jigsaw](\"http:\/\/schools.wrdsb.ca\/athome\/files\/2020\/06\/markus-winkler-vhZgAiA8Zxs-unsplash.jpg\")
<\/p>\nMaterials:<\/h3>\n